Re: [patch] Real-Time Preemption, -RT-2.6.12-rc6-V0.7.48-00

From: Gene Heskett
Date: Sun Jun 12 2005 - 08:42:29 EST


On Sunday 12 June 2005 06:35, Ingo Molnar wrote:
>* Gene Heskett <gene.heskett@xxxxxxxxxxx> wrote:
>> Glitch reports as they develop of course.
>>
>> Q: Whats the diff between turning on hardirq's in mode 3, and mode
>> 4?
>
>well, "mode 3" is PREEMPT_DESKTOP - normal CONFIG_PREEMPT on the
>mainstream kernel. If you turn on hardirq/softirq threading then you
> can e.g. chprio your sound IRQ to have better audio latencies. It
> will cause runtime overhead though. On "mode 4" (PREEMPT_RT)
> hardirq/softirq threading is mandatory (due to the processing
> model).
>
> Ingo

I think I see. Do you have a swag as to how much runtime overhead
using softirq's only might cause? My normal seti production is about
7 per day, and it seems to have dropped to about 6 while running the
RT versions.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
99.35% setiathome rank, not too shabby for a WV hillbilly
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